United States

Department

of Agriculture

Forest Service

Rocky Mountain

Research Station

General Technical

Report RMRS-GTR-149

March 2005

A Strategic Assessment of Forest Biomass and

Fuel Reduction Treatments in Western States

United States Department of Agriculture

Forest Service, Research and Development

In Partnership With The Western

Forestry Leadership Coalition
Abstract Abstract

USDA Forest Service. 2005. A strategic assessment of forest biomass and fuel reduction

treatments in Western States. Gen. Tech. Rep. RMRS-GTR-149. Fort Collins, CO: U.S. treatments in Western States

Department of Agriculture, Forest Service, Rocky Mountain Research Station. 17 p.

http://www.fs.fed.us/research/infocenter.html

This assessment characterizes, at a regional scale, forest biomass that can potentially be

removed to implement the fuel reduction and ecosystem restoration objectives of the

National Fire Plan for the Western United States. The assessment area covers forests on

both public and private ownerships in the region and describes all standing tree volume

including stems, limbs, and tops. Analysis of treatment areas and potential removals is

included. Additionally, the operational systems necessary to effect the treatments as well

as potential erosion impacts, utilization opportunities and market implications were

examined.

Key words: assessment, biomass, fuel reduction, inventory

Prepared by: Prepared by:

Bob Rummer, Jeff Prestemon—USDA Forest Service, Southern Research Station

Dennis May, Pat Miles, John Vissage, Ron McRoberts, Greg Liknes—USDA Forest Service, North

Central Research Station

Wayne D. Shepperd, Dennis Ferguson, William Elliot, Sue Miller—USDA Forest Service, Rocky

Mountain Research Station

Steve Reutebuch, Jamie Barbour, Jeremy Fried—Pacific Northwest Research Station

Bryce Stokes—USDA Forest Service, Vegetation Management and Protection Research Staff

Edward Bilek, Ken Skog—USDA Forest Service, Forest Products Laboratory

With assistance from Bruce Hartsough, University of California-Davis and Glen Murphy, Oregon

State University

Thanks to support from Marilyn Buford, Dave Cleaves, John Sebelius, and Andy Gillespie, USDA

Forest Service, Washington, DC and the comments of many reviewers

Table of Contents Table of Contents

Executive Summary ............................................... 1

The Issue ............................................................. 1

Assessment Objective ............................................ 2

Methodology ......................................................... 2

The Findings .......................................................... 4

Inventory .......................................................... 4

Utilization Options ............................................ 8

Forest Operations for Fuel Reduction .................. 10

Labor Availability ............................................ 14

Sediment Yield................................................ 14

Conclusions ........................................................ 15

References ......................................................... 16

Monument Canyon Research Natural Area,

Santa Fe National Forest, NM.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-149. 2005 1

The Issue

Natural fire cycles have been altered across large areas of the West, changing the vegetative

character of many fire-adapted ecosystems, and increasing wildland fire risk and hazard.

Responding to GAO Report 99-65, the USDA Forest Service outlined a strategy to address

forest health and wildland fire problems in the West (Laverty and Williams 2000). The

Cohesive Strategy and the subsequent 10-year Comprehensive Strategy clearly identify key

components of an effective approach to wildland fire:

a) improve fire prevention and suppression

b) reduce hazardous fuels

c) restore fire-adapted ecosystems

d) promote community assistance

Land management agencies have been

actively addressing the need for both

hazardous fuels reduction and restoration

of fire-adapted ecosystems. In fiscal year

2001, the Departments of Interior and

Agriculture treated 2 million acres across

the nation at a cost of about $200 per acre

(National Fire Plan 2002). Some areas

have been treated with relatively low-cost

methods such as prescribed fire while

others have required more expensive

manual or mechanical operations to

A Strategic Assessment of Forest Biomass and Fuel

Reduction Treatments in Western States

Prescribed fire, Francis Marion National Forest, SC.

Executive Summary

In the 15 Western States there are at least 28 million acres of forest that could benefit

from some type of mechanical treatment to reduce hazardous fuel loading. It is estimated

that about 60 percent of this area could be operationally accessible for treatment with a

total biomass treatment volume of 345 million bone dry tons (bdt). Two-thirds of this

forest area is on public lands. Most of the volume is in trees 6 inches diameter and greater

that have conventional utilization opportunities. Transportation cost and distance to

markets, however, may preclude actual recovery. Treatment costs are increased by the

need to treat large numbers of low-volume stems less than 4 inches in diameter. Gross

costs can range from $35 to over $1000 per acre depending on type of operation, terrain,

and number of trees to be treated. Some areas will likely be prohibitively expensive to

treat, although cost estimates presented here may be high because they are based on the

use of conventional timber harvesting systems applied to small diameter treatments.

Implementation of any significant fuel reduction effort will generate large volumes of

biomass and require the development of additional workforce and operations capacity in

Western forests.
2 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-149. 2005

reduce high fuel loading. Projects have been prioritized with an emphasis on areas that

present risk to communities or significant ecological values.

While managing fire-adapted forests with prescribed fire is often the least expensive option

to reduce hazardous fuels when utilization opportunities are limited, there are many areas

and times where prescribed fire cannot be used. High fuel loadings, air quality restrictions,

short windows of appropriate weather, and risk of escaped fire in the wildland-urban

interface are some of the factors that limit application of prescribed fire. Thus, mechanical

treatments remain an indispensable tool for land managers. However, to implement National

Fire Plan objectives using mechanical treatments, a significant barrier must be overcome—

the disposal and/or utilization of significant quantities of small trees.

There is currently a lack of comprehensive

information about the extent, condition,

biomass volume and characteristics, treatment

opportunities, and potential yields of Western

forests. Planners, contractors, and policymakers

need to know where biomass volumes will be

located and the size-class distributions of the

treated material. Potential markets need

information about material quantities and

characteristics. This report provides a strategic

assessment of biomass in Western forests as a

first step to help address this knowledge gap.

Assessment Objective

The objective of this assessment is to characterize, at a regional scale, forest biomass that

can potentially be removed to implement the fuel reduction and ecosystem restoration

objectives of the National Fire Plan for the Western United States. The assessment area

covers forests on both public and private ownerships in the region and describes all standing

tree volume including stems, limbs, and tops. The assessment includes analysis of treatment

areas and potential removals. Additionally, the operational systems necessary to effect the

treatments as well as potential erosion impacts and utilization opportunities were examined.

Methodology

This strategic assessment estimated current forest conditions for areas needing hazardous

fuel reduction treatments based on the combination of Forest Inventory and Analysis (FIA)1

data and the coarse-scale fire regime assessment by Schmidt and others (2002). The forest

1

 The Forest Inventory and Analysis (FIA) program of the USDA Forest Service has been in continuous

operation since 1930. FIA collects, analyzes, and reports information on the status and trends of America’s

forests: how much forest exists, where it exists, who owns it, and how it is changing. The latest technologies

are used to acquire a consistent core set of ecological data about forests through remote sensing and field

measurements. The data in this report are summarized from 37,000 permanent field plots in the Western

United States.

Thinning slash pile, Coconino National Forest.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-149. 2005 3

inventory data presents an estimated “snapshot” of stand conditions at the present time.

Potential removal volumes were identified based on selective removal prescriptions using

the Stand Density Index (SDI) criterion. SDI (Reineke 1933) is a long-established, sciencebased forest stocking guide that can be adapted to uneven-aged forests (Long and Daniel

1990) using data available from broad-scale inventories. Using an SDI criterion allowed a

uniform prescription approach across a wide range of ecosystems.

The FIA plot data were summarized by forest type and ecoregion, and specific SDI-based

prescriptions were developed for each combination. The basic approach was to reduce stand

density to 30 percent of maximum SDI for the given stand. Removals generally came from

small to mid-size trees. However, larger trees could also be removed if SDI surpluses occurred

in those size classes. There was no upper diameter limit imposed on the prescription.

Figure 1 illustrates an SDI-derived treatment applied to a ponderosa pine forest type in

Colorado.

Figure 1—Example of an SDI-defined removal in a ponderosa pine forest type.

Since the prescriptions were developed for very large areas (regional forest types), they

statistically describe average forest conditions over the landscape, not specific forest stands.

Actual stocking may exist on the ground as uneven-aged forests, or as clumps, groups, or
4 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-149. 2005

dispersed stands of even-aged trees. The landscape level uneven-aged approach allows a

wide variety of management prescriptions at operational scales to accommodate old-growth,

threatened and endangered species, wildlife habitat, insect outbreaks, watershed protection,

and other ecologic and multiresource objectives. The SDI prescription was selected to provide

an ecologically based conservative estimate of removal volume, so as to assure that the

projected biomass outputs are attainable at broad scales. Specific treatments to address fuel

loading in a given stand should be based on assessment of predicted fire behavior.

This assessment does not define a preferred fuel reduction management prescription for a

particular forest stand. However other work has examined the impact of selective cutting

prescriptions on fire behavior in Western forests. While removal of submerchantable

seedlings and saplings is important to reduce ladder fuels, thinning only small material

does little to reduce crown fire spread (Keyes and O’Hara 2002). Fiedler and others (2001),

for example, found that a comprehensive selection treatment, removing some trees from all

diameter classes, had a more significant effect on reducing measures of fire risk than

removing only small trees.

The potential removal volumes that would result from the application of these prescriptions

were summarized by forest type and state. Using the diameter and volume distributions of

the removals, operational costs to implement basic fuel reduction treatments were estimated

using a harvesting cost model. Production functions incorporated into the model are based

on existing conventional forest harvesting technology. Regional comparisons of sediment

yield from thinning, prescribed fire, and wildfire were developed using the Disturbed WEPP

program (Elliot and others 2000).

The removal volumes were also partitioned into two potential utilization groups—stem

volume of trees greater than 7 inches diameter at breast height (dbh) taken to a 4-inch

minimum top diameter (merchantable volume); and all the remaining volume from small

trees, limbs, and tops (biomass volume). Merchantable volumes in board feet were

estimated by converting the weights to cubic volumes and then by converting the cubic

volumes into board feet using conversions given in Haynes (1990). Weights were converted

to cubic volumes based on density factors for ponderosa pine and lodgepole pine found in

USFS (1999).

Discussion of current Western manufacturing technology is based on the draft 2002 RPA

(USFS 2002).

The Findings The Findings

Inventory

The 15 Western States encompass almost 1 billion acres of land, of which 236 million acres

are forested. Slightly more than half of the forested area (130 million acres) is classified as

timberland according to standard definition (capable of growing at least 20 cubic feet per

acre per year and not reserved by law or administrative action from timber harvest; Smith

and others 2001). Treatment opportunities exist on timberland areas that have stocking in
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-149. 2005 5

excess of the residual stocking specified by the SDI-based prescription. Using this criterion,

treatment opportunities exist on three-quarters of the timberland area (table 1).

Treatable areas were further classified by Fire Regime Condition Class (FRCC)—a measure

of how much a forest has departed from natural wildland fire conditions (Schmidt and

others 2002). The fire regime in Class 2 areas is moderately altered from the historical

range. Moderate levels of restoration treatments such as fire or mechanical treatments

would be required to begin managing a more natural fire cycle. In Class 3 areas, fire

regimes have been significantly altered and there is a high risk of losing key ecosystem

components in a wildfire. Due to high fuel loadings, mechanical treatments are expected to

be needed before the reintroduction of fire. This assessment estimates a total of 67 million

treatable acres in FRCCs 2 and 3. About half of those acres (28.5 million) are in the highrisk FRCC 3.

Table 1—Assessment area statistics by State.

Land area Treatment opportunities

(million acres) (million acres)

State Total Forestland Timberland Timberland Class 2 + 3 Class 3

AZ 72.7 19.4 3.5 3.1 2.9 1.9

CA 99.8 40.2 17.8 13.4 11.8 5.5

CO 66.4 21.4 11.6 9.5 6.0 2.5

ID 53.0 21.6 16.8 12.1 8.0 3.3

KS 52.4 1.5 1.5 1.3 0.4 0.2

MT 93.2 23.3 19.2 14.3 9.5 3.7

NE 49.2 0.9 0.9 0.7 0.1 *

NV 70.3 10.2 0.4 0.2 0.1 *

NM 77.7 16.7 4.4 3.9 3.3 2.1

ND 44.2 0.7 0.4 0.4 * *

OR 61.4 29.7 23.8 16.9 12.2 5.6

SD 48.6 1.6 1.5 1.1 0.9 0.6

UT 52.6 15.7 4.7 3.6 1.2 0.1

WA 42.6 21.8 17.3 12.4 8.5 2.5

WY 62.1 11.0 5.7 4.0 1.9 0.4

Total 946.1 235.7 129.6 96.9 66.9 28.5

* less than 100,000 acres

Class 2 areas need prescribed fire or mechanical treatment to restore ecosystem function

Class 3 areas need mechanical treatment prior to using fire as a restorative tool
6 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-149. 2005

The total standing timberland volume is nearly 6.9 billion bone dry tons (bdt), including the

volume of stems, limbs, and tops. Treating all “overstocked” Western forests would remove

just over 2 billion bdt (table 2). Focusing only on areas that would require mechanical fuel

reduction before fire can be used as a management tool (Class 3) could yield 576 million bdt.

About two-thirds of the potential treatment volume is located on National Forest lands

(62 percent). About 30 percent of the treatment volume would come from private lands

and the remaining 8 percent is on State, local and other Federal ownerships. See figure 2.

Figure 2—Distribution and volumes on Class 2 and 3 forests in the Western United States.

While the assessment already excludes reserved forests and low-productivity forests, it is

unrealistic to assume that all of the remaining area could be accessed for operational

treatments. Steep slopes, sensitive sites, regeneration difficulty, or lack of adequate resource

information may exclude an area from operational treatment. According to a global analysis

(FAO 2001) about 60 percent of the North American temperate forest is considered

accessible (not reserved or high elevation and within 15 miles of major transportation

infrastructure). A summary of National Forest land management plans from 1995 also found

that about 60 percent of the Western National Forest timberland base is considered

“suitable” for timber production operations (this is only 37 percent of the forestland base).

The determination of “suitable” indicates that current forest operations technology would
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-149. 2005 7

Table 2—Standing and removal volume by State.

Total forest volume Volume to remove

(million bone dry tons) (million bone dry tons)

All Treatable Class Treatable Class

State timberland timberland 2 + 3 Class 3 timberland 2 + 3 Class 3

AZ 138.3 134.0 126.4 85.1 61.3 57.8 39.5

CA 1,328.3 1,252.4 1,094.5 483.2 368.1 317.9 125.1

CO 436.1 413.7 250.6 117.8 165.3 99.9 48.3

ID 772.3 704.3 498.7 217.9 242.9 177.6 80.4

KS 52.4 51.0 13.4 5.6 21.9 6.1 2.5

MT 733.7 688.8 485.9 197.9 271.3 188.2 77.4

NE 31.2 28.6 5.9 1.2 11.5 2.1 0.5

NV 11.9 9.5 6.0 2.0 2.8 1.7 0.5

NM 154.8 150.2 129.1 85.3 57.5 49.6 32.2

ND 14.0 13.3 0.8 0.1 5.5 0.3 *

OR 1,629.3 1,534.7 1,037.5 358.4 436.6 291.1 91.0

SD 39.9 35.1 29.7 20.7 11.1 9.0 6.6

UT 155.8 144.6 43.0 4.0 54.5 15.6 1.6

WA 1,159.2 1,101.5 722.8 194.1 371.5 241.5 63.0

WY 197.9 185.6 84.8 17.8 72.1 34.7 7.5

Total 6,855.0 6,447.4 4,529.1 1,791.1 2,154.0 1,493.4 576.1

* less than 50,000 bdt

Class 2 areas need prescribed fire or mechanical treatment to restore ecosystem function

Class 3 areas need mechanical treatment prior to using fire as a restorative tool

not produce irreversible damage to soil or water resources. The accessible area of private

lands may be higher. Even assuming that only 60 percent of the treatable timberland on all

ownerships in FRCC 3 is accessible for fuel reduction operations would still require

treatment of 346 million bdt.

The vast majority of the trees identified for removal by the SDI prescriptions would be less

than 10 inches dbh (fig. 3). There are nearly 2 billion trees in the 2-inch diameter class alone.

While 86 percent of the trees that would be cut are less than 10 inches, most of the volume

that would be treated comes from the 14 percent of the trees that are larger than 10 inches in

diameter. This is the central dilemma of fuel reduction treatments—large numbers of small

diameter trees with relatively little volume that can be feasibly utilized must be treated.

Figure 3—Diameter distribution of trees and volume removed in the SDI prescriptions (Vissage

and Miles 2003). Both distributions continue to tail off beyond 22-inch diameter.
8 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-149. 2005

Utilization Options

The range of potential recovery volumes is huge. At the upper end, if all volume were

recovered from thinning treatments on the 97 million acres of treatable timberland, about

617 million bdt of nonmerchantable biomass that is typically left on site (limbs, tops, and

saplings) and 1,537 million bdt of merchantable timber would be generated. At the lower end,

if material were only recovered from the estimated 60 percent of the high-risk (Condition

Class 3) areas, about 101 million bdt of nonmerchantable biomass and 245 million bdt of

merchantable timber would be recovered. If the treatments were spread over 30 years, the

annual production would range from 8 million to 51 million bdt of merchantable forest

products. This volume doesn’t even consider the additional forest growth that would occur

over that period.

A breakdown of the size distribution of this material (fig. 3) shows that more than half of

the volume would come from trees greater than 13 inches dbh and about three-fourths

would come from trees greater than 9 inches dbh. These sizes of trees are well within the

current merchantability limits of processing facilities operating in the West.

In 1999, Western forest industry processed about 28 million bdt of roundwood for lumber

and 2.2 million bdt for pulpwood (Howard 2001). The draft 2002 RPA (USFS 2002)

estimates 32 million bdt of annual growing stock removals in the West are currently going

to all products including medium-density fiberboard (MDF) plants, particle board plants,

pulpwood, and hog fuel. This means that at the upper end of the potential range, broadscale

implementation of mechanical fuel reduction could produce nearly twice as much material

(51 million bdt) as is currently being processed in the West. Even recovering material only

from accessible, high-risk stands would constitute about 25 percent (8 million bdt) of the

current conventional processing volume.

Volume from thinning treatments could either replace current sources of raw material within

the existing manufacturing infrastructure or it could require investment in new facilities.

The market price impacts could range from practically nil to very large. For example, a

program that would mechanically reduce fuels on all Condition Class 2 and 3 forestlands

and that simply added to current harvests would imply total region harvests of 83 million bdt

and large aggregate price reductions. Any fuel reduction program considered at that scale

would probably involve large program outlays for participating government agencies and

(or) a system of incentives for private landowners. Price reductions arising from such a

program would negatively impact nonparticipating forestland owners through lower timber

prices, as well. A program that only addressed fuels on the Condition Class 3 lands but that

replaced 8 million bdt of existing harvests would likely have very little if any aggregate

price impact, although some local effects would be experienced.

New mills and processing capacity expansions at existing mills would moderate any

negative market price effects arising from any large-scale program. If substantial new

processing capacity were expected as a result of the large fuel reduction program, then
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-149. 2005 9

negative price and welfare impacts could be minimized over time by expanding treatment

volumes in step with capacity expansions. If no new capacity were expected, then price

effects would certainly be negative because local processing capability would be fixed by

the maximum local production capacity. New mills could include nonconventional sawmills

(small mills that are less expensive to

construct than conventional mills but have a

lower lumber recovery), biomass-fired power

plants, or traditional facilities such as pulp

mills, sawmills, or particleboard plants.

Table 3 lists general ranges of processing

capacities for current technology. There are

numerous specialty markets for small-diameter

material such as post-and-rail, rustic furniture,

firewood, animal bedding, and composts.

While these facilities are important for local

economic development using material from

fuel reduction treatments, their scale of operation is significantly smaller than the product

applications in table 3. Levan-Green and Livingston (2001) review a wide range of potential

uses for small-diameter trees.

Small-log sawmill—Bonner’s Ferry, ID.

Table 3—Ranges of individual mill capacity for product lines using materials removed during fuel

reduction treatments.

Roundwood consumption Lumber output

(bdt/year) (MBF/year)

Facility type Low High Low High

Pulp mill 150,000 750,000

Conventional sawmill 35,750 180,000 20,000 100,000

Non-conventional sawmill 22,750 45,000 10,000 20,000

OSB plant 300,000 500,000

MDF or particleboard 200,000 300,000

Cogen (steam and power) 175,000 350,000

Avista biomass power plant-Kettle Falls, WA.

Biomass (tops, limbs, and saplings)

from thinning operations as well as

hog fuel produced during the

manufacture of lumber, chips, and

Oriented Strand Board (OSB) could be

used for cogeneration of electricity for

sale into the power grid and process

steam useful in manufacturing

operations or other applications. The

clean chips generated as residues from

lumber processing could be used for

pulp production or MDF and

particleboard production. Stems of

trees less than 7 inches in diameter

could be used for pulp chips or OSB.
10 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-149. 2005

The potential size of the manufacturing infrastructure needed to process material from fuel

reduction treatments is large. For example, to process the merchantable volume from only

the Class 3 fuel reduction treatments will require the capacity of about 75 average-sized

conventional sawmills for 30 years. Whether these would be existing facilities, restarted

mills, or new construction would depend on many factors. The economics of establishing

such a large number of processing facilities is highly uncertain. Attracting investment to

new processing infrastructure involves analysis of long-term supply and market forecasts.

Today’s forest products markets are global, and Western production will have to compete

with material from other wood producing regions. There are considerable challenges

associated with establishing new processing plants in the West that go well beyond

implementation of the fuel reduction treatments.

A complete analysis of the market effects as well as program costs will be conducted under

a separate Joint Fire Science Program study, “A national study of the economic impacts of

biomass removals to mitigate wildfire damages on Federal, State, and private lands.” This

study seeks to evaluate market price and other economic effects of alternative scales of fuel

reduction programs, with emphasis on wildland-urban-interface zones. The study will also

evaluate the differential effects of fuel reduction harvests that produce merchantable

materials that substitute for or add to existing regional harvests. Preliminary results of that

analysis were expected in late 2004, with final results available in mid-2005.

Forest Operations for Fuel Reduction

Prescribed fire is usually the least expensive option for reducing fuel loading when it can be

used. This treatment mimics natural processes for maintaining stocking. Cleaves and others

(2000) examined National Forest prescribed fire programs and found that across the Western

National Forests, prescribed management-ignited fires averaged $92 per acre. However,

the need for prescribed fire was nearly double the area actually treated. Key restrictions on

opportunities for burning included air quality and smoke management regulations, limited

acceptable weather conditions, and lack of resources. High fuel loading was also an issue in

some of the Western National Forest Regions.

When prescribed fire is not a viable option, there is a wide range of technology available from

chainsaws to sophisticated harvesters (table 4), although few of these have been designed

specifically for fuel reduction applications. Managers face the challenge of selecting a

system to create the desired fuel conditions while minimizing adverse ecological impacts

and meeting economic constraints. Some systems may provide for extraction of usable

material while others may simply alter fuel conditions or form on site (fig. 4). The “best”

technology for treating fuels may not always be the least expensive and will vary from stand

to stand. Generally, the great challenge of fuel reduction treatments is the need to process or

treat a large number of small-diameter stems. The individual handling time (and consequently

cost) adds up quickly even though the total volume handled may be relatively low. If small

diameter trees are not removed during fuel reduction treatments, they will soon grow to

become ladder fuels that spread wildfires to larger trees. Even though it may not be

economical to remove small diameter trees and forest residues, most of them should be

treated to prolong the beneficial effects of fuel reduction.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-149. 2005 11

Table 4—Generic comparison of fuel reduction treatment alternatives.

Treatment Cost range Key benefit Key problem Products?

Prescribed fire $35-300/ac Low cost Restricted use No

Mastication in-woods $100-1000/ac No smoke Fiber left in-woods No

Cut/pile/burn $100-750/ac Low access Burning limitations No

Cut/skid $30-40/bdt Offsets costs Soil impacts Yes

Cut/skid/chip $34-48/bdt Usable fiber High cost, low value Yes

Chipping thinned material, Boise National Forest, ID.

Figure 4—Operational functions in fuel reduction treatments.

If the treated material has no potential

product value, there are several

approaches that leave material in the

stand. About 30 percent of the total

biomass to be treated on Class 3

timberland consists of saplings, limbs,

and tops. Felling and piling, either

with manual crews or mechanized

equipment, is widely applied. The

piles are subsequently burned under

controlled conditions. Mobile mulching

or shredding machines can also be

used to reduce stand density. This

equipment changes the size distribution

of forest fuels, producing chunks and

sticks that decay naturally in the forest.

In some areas it may be necessary to remove the saplings, limbs, and tops from the forest to

reduce fuel loading or to extract usable fiber. Moving this material across the landscape can

be achieved with people, small machines, large-capacity forwarders, cable systems, or

helicopter transport. The selection and cost of the extraction system are very dependent on

terrain, material size, and the distance moved and must be designed and optimized to

specific stand and terrain conditions to be economically efficient. When material in fuel
12 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-149. 2005

reduction treatments can meet

product specifications, extraction

and processing may help offset the

cost of stand treatment. Operations

to recover products may range from

small-scale systems for products

such as post-and-rail or firewood to

fully mechanized systems that

combine log length recovery with

slash treatment. The costs of

product handling per unit volume

generally increase with decreasing

stem diameter, particularly when

using equipment designed for

handling conventionally merchantable

wood. This makes small-diameter

treatments less cost-effective and

highlights the need for development

of more cost-effective systems.

A new harvesting cost model, called ST Harvest (Fight and others 2003), predicts costs for

fuel reduction/forest health thinning in natural stands. It considers factors of tree size,

removal volume per acre, harvest system, unit size, and extraction distance. Current model

equations are based on older production studies of conventional operations due to a lack of

studies of new fuel reduction treatment systems. Estimated gross treatment costs for cutand-skid vary greatly depending on stand conditions and forest type (table 5). These costs

assume that all cut trees less than 3 inches dbh are left in the stand, trees between 3 inches

and 7 inches dbh are cut, taken to roadside and chipped, and trees larger than 7 inches are

taken to roadside for processing into products. The costs also include some brush treatment

and site rehabilitation. For the Western forest types shown in table 5 there is a wide

variation in per acre treatment costs because of variations in the number of trees per acre

and the treatment volume removed.

There have been developments in equipment specifically designed for treating small

material, but more information needs to be acquired on costs, performance, and

compatibility with fuel reduction objectives. Mulching machines, purpose-built small

diameter harvesters, and other technologies need additional evaluation.

Processing small-diameter logs—Medicine Bow

National Forest, WY.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-149. 2005 13

Table 5—Estimated gross operational cost to cut and extract fuel reduction material to roadside.

Total cut Removed Treatment cost ($/ac) Gentle

Forest type trees/ac Bdt/ac trees/ac Bdt/ac Gentle Rolling ($/bdt)

SW ponderosa pine 360 12.5 92 12.2 680 830 55.74

Intermountain ponderosa 85 11.4 82 11.4 630 780 55.26

Intermountain lodgepole 255 22.5 161 22.1 1000 1220 45.24

Sierras ponderosa 134 13.5 82 13.4 600 730 44.78

Sierras lodgepole 463 12.3 105 12.1 700 860 57.85

Rockies ponderosa 188 9.8 85 9.6 590 720 61.46

Rockies lodgepole 378 23.2 263 22.9 1120 1330 48.91

Great Basin ponderosa 75 4.6 63 4.6 400 490 86.96

Great Basin lodgepole 302 38.6 240 38.6 1340 1630 34.72

Accessibility and terrain are key factors limiting operational treatments for fuel reduction.

Mobilizing and supporting crews and equipment working in the forest requires some

amount of road or trail access. Steep terrain and sensitive sites also commonly limit

operational management in Western forests. The Western National Forests average only 60

percent of timberland as “suitable” for timber production—indicating the difficulty of

operation in many areas. While access and slope do not necessarily preclude fuel reduction

treatments (treating biomass on site may still be feasible with limited road access) it

significantly reduces economically viable opportunities for product recovery.

The ability to separate and market larger diameter logs for higher value products is critical

to the net revenues or costs of fuel treatments. If the opportunity to utilize larger diameter

logs for higher valued products is lacking, then revenues would not cover costs on all the

Western forest types studied (table 6).

Table 6—Estimated revenues minus fuel treatment costs with larger diameter logs sold for higher value products

or, alternatively, for chips.

Total Net revenue (cost) with Net (cost) with larger

merchantable higher value products diameter logs sold for chips

(>7" dbh) ($/ac) ($/ac)

Forest type MBF/ac Bdt/ac Gentle Rolling Gentle Rolling

SW ponderosa pine 5.3 11.3 $496 $346 $(1,176) $(1,326)

Intermountain ponderosa 4.8 10.4 $433 $283 $(1,090) $(1,240)

Intermountain lodgepole 8.4 18.7 $673 $453 $(1,886) $(2,106)

Sierras ponderosa 5.4 11.7 $615 $485 $(1,138) $(1,268)

Sierras lodgepole 4.7 10.7 $247 $87 $(1,184) $(1,344)

Rockies ponderosa 4.5 8.4 $465 $335 $(975) $(1,105)

Rockies lodgepole 8.3 15.8 $614 $404 $(2,015) $(2,225)

Great Basin ponderosa 1.7 3.7 $(16) $(106) $(583) $(673)

Great Basin lodgepole 14.5 32.0 $1,562 $1,272 $(2,881) $(3,171)

Underlying assumptions:

Ponderosa pine value = $300/thousand board feet at the mill

Lodgepole pine value = $280/thousand board feet at the mill

Chip value = $30/bone dry ton at the mill

Mill distance = 100 miles

Transport cost = $0.35/bone dry ton mile
14 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-149. 2005

Transportation costs are also a significant factor in the cost of recovering biomass for

utilization. As much as half the cost of the material delivered to a manufacturing facility

may be attributed to transportation. Recent studies have cited haul rates from $0.20 to

$0.60/bdt-mile, depending on truck configuration, travel speeds, and payload factors.

Hauling costs determine the economically viable distance between the forest treatment site

and a processing facility. Assuming chip values of $30/bone dry ton delivered to the mill

and chip transport costs of $0.35/bone dry ton-mile, the maximum distance that chips can be

transported without additional subsidies is 86 miles. At this distance, the chip value just

covers the transport cost, and no fuel treatment costs are recovered.

Labor Availability

Another key issue is the availability of sufficient numbers of

skilled labor and appropriate equipment to perform fuel

reduction treatments. This is a question of both adequate

numbers of workers and their proximity to areas where work

needs to be done. If workers and equipment have to be

mobilized across large distances, costs will be higher and

competition for contract projects will be reduced. There

would also be a need for sufficient qualified agency personnel

to plan and administer a fuel reduction program.

Forestry workers represent a skilled workforce that will likely

be the foundation of any significant fuel reduction program.

Given recent reductions in Federal timber harvests, a pool of

skilled labor may still exist in some areas. However, not all

the labor resides in areas where fuel reduction treatments

would be concentrated. Because the Western United States has

been managed less intensively than other regions of the country,

the availability of trained forestry workers is lower per acre of forestland. Based on 1990

census data, the Western United States averaged 10.2 forest workers per 100 mi2

 of

forestland (compared to 15.4 in the South, for example). Assuming a 30 percent drop in

Western timber removals since 1990, the currently available workforce in the West may be

about 6.4 forest workers per 100 mi2 forestland. The disparity between the distribution of

the forestry workforce and the forestlands requiring fuel reduction can be appreciated by

overlaying the Condition Class 2 and 3 areas with logging contractor distribution (fig. 5).

Sediment Yield

Mechanical operations on the ground have the potential to create site disturbance and

adverse effects. One of the most significant concerns associated with forest operations is the

potential impact on water quality. Three alternative fuel treatments were compared across

Western ecoregions using the Disturbed WEPP erosion prediction model (Elliot and Miller

2002). On a per unit area affected basis, wildfire is predicted to produce nearly 70 times as

much sediment as a thinning treatment (table 7). Prescribed fire treatments are estimated to

yield about 1.6 times more sediment than thinning.

Manual chainsaw

work, Wyoming.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-149. 2005 15

Figure 5—Availability of logging contractors for Condition Class 2 and 3 areas.

Table 7—Summary of forest sediment yields for fuel reduction alternatives.

Sediment yield

Slope class Mean Min Max

Thinning (tons/mi2

) Low 24.2 0.0 364.8

Moderate 41.9 0.0 608.0

Prescribed fire (tons/mi2

) Low 38.4 0.0 339.2

Moderate 67.7 0.0 518.4

Wildfire (tons/mi2

) Low 1639.6 25.6 10873.6

Moderate 2729.5 51.2 17971.2

Conclusions Conclusions

The total volume to be treated, even based on just estimated accessible areas, represents a

large amount of material (345 million bdt)—nearly 10 times the annual conventional timber

harvest of the region. Most of the volume that should be removed can be utilized in

conventional forest products processing facilities if markets are within economically viable

transport distances. While most of the volume can be used, there is also a need to treat large

numbers of small trees that will yield relatively little volume. The operational cost of

treating the smallest trees may exceed the market value of any recovered fiber. The most

cost-effective systems may be operations that leave processed material in the forest without

attempting to utilize marginal volumes.
16 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-149. 2005

Implementing a fuels reduction program will affect markets, manufacturers, and contractors.

Utilizing the volume that can be recovered for products will either require new processing

capacity and markets or it will replace existing sources of raw material in current facilities.

Initiating a West wide fuel reduction program will require contractors to shift operations

toward a different type of forest treatment, with an emphasis on methods that can efficiently

handle small-diameter material. Researchers, equipment manufacturers, and industrial fiber

users will need to develop appropriate operational specifications for this new application.

The economic and infrastructure demands of implementing a fuels reduction program will

depend to a large degree on the scale of operation. Clearly a fuel reduction program that

seeks to address forest conditions across the region would have more significant impacts

than a fuel reduction program focused principally on high-risk urban interface areas.

Initial estimates of sediment yield from alternative treatments clearly indicate that active

management is less detrimental than wildfire on an area-affected basis. Steeper ground and

wetter ecoregions showed higher sediment yields than lower slopes or drier sites. On a

landscape level, the cumulative effect would depend on the scale of treatment. However,

given the overall average sediment yields, the effect of 70 acres of thinning treatment would

be about the same as the effect of 1 acre consumed in wildfire.

Finally, the development of this assessment highlights the value of having the ability to

measure and describe the forest resource in common terms across a large landscape. To

monitor and assess the dynamic changes in Western forest fuel conditions it will be

necessary to provide inventory updates, expand inventory data collection to better assess

small-diameter stocking and growth, and develop easily accessible databases and tools for

specific tactical planning and implementation. Research work also needs to be done to

develop and test new technologies for treating forest biomass in the stand. Better

information about the productivity and cost of specialized systems for fuel reduction

treatments should be pursued. Conventional timber harvesting equipment should also be

evaluated for use in fuel reduction treatments. The large volumes that may be available offer

opportunities for recovery and utilization. There is a need to develop more effective

utilization and higher valued products from small-diameter material.

The National Fire Plan has made a commitment to address the problem of overstocked

Western forests. This assessment has defined the magnitude of the task and identified some

of the operational issues that will affect implementation.

References References

Cleaves, David; Martinez, Jorge; Haines, Terry. 2001. Influences on prescribed burning activity and costs in

the National Forest System. Gen. Tech. Rep. SRS-37. Asheville, NC: U.S. Department of Agriculture, Forest

Service, Southern Research Station. 34 p.

Elliot, W.J.; Miller, I.S. 2002. Estimating erosion impacts from implementing the National Fire Plan.

Paper 02-5011. St. Joseph, MI: American Society of Agricultural Engineers. 25 p.

Elliot, W.J.; Scheele, D.L.; Hall, D.E. 2000. The Forest Service WEPP interfaces. Paper 00-5021. St. Joseph,

MI: American Society of Agricultural Engineers. 9 p.

FAO. 2001. Global forest resources assessment 2000. Forestry Paper 140. Rome: Food and Agriculture

Organization of the United Nations. Pp. 75-80.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-149. 2005 17

Fiedler, C.; Keegan, C.; Woodall, C.; Morgan, T.; Robertson, S.; Chmelik, J. 2001. A strategic assessment of

fire hazard in Montana. Report submitted to the Joint Fire Sciences Program. http://jfsp.nifc.gov/

ummontanarpt.pdf. 39 p.

Fight, R.D.; Zhang, X.; Hartsough, B.R. 2003. User’s guide for STHARVEST, software to estimate the cost of

harvesting small timber. Gen. Tech. Rep. PNW-GTR-582. Portland, OR: U.S. Department of Agriculture,

Forest Service, Pacific Northwest Research Station. 12 p.

Haynes, R.W. 1990. An analysis of the timber situation in the United States: 1989-2040. Gen. Tech. Rep.

RM-199. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and

Range Experiment Station. Table B-9.

Howard, James. 2001. U.S. timber production, trade, consumption, and price statistics 1965-1999. Res. Pap.

FPL-RP-595. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory.

90 p.

Keyes, C.; O’Hara, K. 2002. Quantifying stand targets for silvicultural prevention of crown fires. Western

Journal of Applied Forestry 17(2): 101-109.

Laverty, L.; Williams, J. 2000. Protecting people and sustaining resources in fire-adapted ecosystems. A

cohesive strategy. Washington, DC: U.S. Department of Agriculture, Forest Service.

Levan-Green, S.; Livingston, J. 2001. Exploring the uses for small-diameter trees. Forest Products Journal.

51(9): 10-21.

Long, J.N.; Daniel, T.W. 1990. Assessment of growing stock in uneven-aged stands. Western Journal of

Applied Forestry 5(3): 93-96.

National Fire Plan. 2002. National fire plan. Hazardous fuels reduction. http://www.fireplan.gov/

hazfuels_1_28_02.cfm (26 March 2003).

Reineke, L.H. 1933. Perfecting a stand density index for even-aged forests. Journal of Agricultural Research

46: 627-638.

Schmidt, Kirsten M.; Menakis, James P.; Hardy, Colin C.; Hann, Wendall J.; Bunnell, David L. 2002.

Development of coarse-scale spatial data for wildland fire and fuel management. Gen. Tech. Rep. RMRSGTR-87. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research

Station. 41 p. + CD.

Smith, W. Brad; Vissage, John S.; Darr, David R.; Sheffield, Raymond M. 2001. Forest Resources of the

United States, 1997. Gen. Tech. Rep. NC-219. St. Paul, MN: U.S. Department of Agriculture, Forest

Service, North Central Research Station. 190 p.

USFS. 1999. Wood handbook: Wood as an engineering material. Gen. Tech. Rep. FPL-GTR-113. Madison, WI:

U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. Table 3-7a.

USFS. 2002. Forest resources of the United States: Draft 2002 RPA Tables. http://www.ncrs.fs.fed.us/4801/

fiadb/rpa_tabler/Draft_RPA_2002_Forest_Resource_Tables.pdf (2 March 2003).

Vissage, J.S.; Miles, P.D. 2003. Fuel-reduction treatment: a west-wide assessment of opportunities. Journal of

Forestry 101(2): 5-6.
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